1. Field of the Invention
The present invention relates to a semiconductor device and a method for fabricating the same, and more particularly, to a semiconductor device in which a storage dielectric film and a storage electrode included in the capacitor is transferred from an inactive region of a semiconductor substrate to the active region thereof, i.e., into a device isolating trench such that the capacitor is prevented from unnecessarily occupying an active region of a semiconductor substrate while maintaining its proper function, and a method for fabricating the same.
2. Discussion of the Related Art
Recently, the level of integration of a semiconductor device has rapidly progressed, a geometrical structure of each structural element of the semiconductor device has also been greatly reduced.
As illustrated in FIG. 1, in a semiconductor device in accordance with a related art, a semiconductor substrate 1 is divided and defined as an inactive region (FR) and an active region (AR) by a device separating film 2. In this case, in the active region (AR) of the semiconductor substrate 1, a transistor 10 for selectively switching a flow of electric charge, and a capacitor 20 for storing the electric charge switched by the transistor 10 are closely connected with each other.
In this case, the transistor 10 includes a gate insulating film pattern 11, a gate electrode patter 12, and a source/drain diffusion layer 14. The capacitor 20 includes a storage dielectric film 21 and a storage electrode 22.
In this case, the storage dielectric film 21 and the storage electrode 22 included in the capacitor 20 are formed in a trench 23 buried in the semiconductor substrate 1. In this instance, a portion 22a of the storage electrode 22 is exposed on a surface of the semiconductor substrate 1 and electrically connected with the source/drain diffusion layer 14 of the transistor 10.
As recognized by the present inventor, as semiconductor devices have become more highly integrated, a problem of reducing the active region (AR) acts as an important factor in determining a quality of a finished semiconductor device.
Nevertheless, as aforementioned, since the conventional capacitor 20 includes a trench structure and additionally occupies a portion of the active region (AR), if no separate measures are taken, the size of the active region (AR) of the semiconductor device largely increases as much as that of an occupied region of the capacitor 20. Therefore, it becomes more difficult to reduce the active region (AR) of the semiconductor device in accordance with the related art.
Of course, the size increase problem of the active region (AR) is somewhat assuaged when the structure of the capacitor 20 is changed from the abovementioned trench type structure to a stack type structure. However, as recognized by the present inventor in this case, a serious problem additionally occurs that an overall step height of the semiconductor device is unnecessarily increased as much as a height of the stacked capacitor 20.